The present invention relates to an information storage medium, a method of fabricating this medium, and a drive unit for such a medium. More particularly, the invention relates to an information storage medium having information storage portions performing different methods of recording and a drive unit such as a disk drive capable of writing and reading information to and from such an information storage medium.
Read-only optical storage media such as CD-ROMs are typical information storage media. Since these read-only optical storage media have large storage capacities, they are used in game machines and in other applications. However, it is difficult to rewrite the contents of the read-only optical storage media. Therefore, it is impossible to record intermediate results of processing. A photoelectromagnetic storage disk has been developed as a rewritable disk having a large storage capacity. Unfortunately, this disk is very expensive. In addition, this disk is not compatible with conventional optical storage disks. Therefore, at present, none of these information storage media can fully meet the needs.